This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-046437, filed Feb. 24, 1999; and No. 2000-038526, filed Feb. 16, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a digital camera to which a lens can be attached and to a dirt position detecting method for the digital camera.
A digital camera which photographs an image by a solid-state image sensor device such as a CCD and stores the obtained image data in a storage medium such as a memory or a hard disk becomes widespread.
A digital camera whose lens can be interchanged is also commercially available like a camera which transfers image data onto a film. However, in the case of the digital camera whose lens can be interchanged, there is a problem that dirt or dust (which are collectively called xe2x80x9cdirtxe2x80x9d, hereinafter) is adhered to the image sensor device, an image sensor device protecting glass fixed on the image sensor device, a surface of a filter and the like, or an optical system when the lens is interchanged. There is a problem that in the case of an image which was shot in a state where dirt is adhered, since light does not enter a picture element portion on which dirt is adhered, image failure is caused.
It is an object of the present invention to provided a digital camera which can correct the degradation of image quality of a shot image even if dirt is adhered to an image sensor device, an image sensor device protecting glass fixed on the image sensor device or a filter when the lens is interchanged, and to provide a dirt position detecting method for a digital camera for detecting a position of dirt which causes image failure.
A digital camera of the present invention whose lens is detachable, comprises: a judging section for judging whether an image failure is caused due to dirt adhering on an image sensor device unit including image sensor device; an illuminating member which is disposed in the vicinity of the image sensor device unit such that irradiation light can enter the image sensor device and which is driven when at least the judgment is made; a memory for storing a position of a picture element of the image sensor device corresponding to image sensor data causing image failure when the judging section judged that image failure has been caused; and a correcting section for correcting the image sensor data output from the image sensor device unit based on image position data stored in the memory when a picture is photographed after the lens is interchanged.
Preferable modes of this semiconductor device are as follows:
(a) The digital camera further comprises a liquid crystal display for displaying the image data output from the image sensor device unit, wherein the illuminating member also serves as a backlight which irradiates illumination light from a back side of the liquid crystal display.
(b) The correcting section corrects the image sensor data which correspond to picture element position data stored in the memory and which were output after the lens was interchanged, based on image sensor data corresponding to picture element position adjacent to the picture element position data.
(c) The digital camera further comprises a warning section for warning of a user of the fact that there exists a picture element which can not be corrected when the image sensor data could not be corrected by the correcting section. The warning section warns when the number of picture elements which are adjacent to the picture element position data stored in the memory and which continuously cause image failure is greater than the predetermined number. The warning section warns when the lens is interchanged or a power supply is turned on.
(d) The image sensor device unit comprises at least one of a protecting glass for protecting a surface of the image sensor device, and a filter.
(e) A picture element defect owned by the image sensor device itself is stored in the memory, and the correcting section corrects an image failure owned by the image sensor device itself.
(f) The correcting section corrects the image sensor data which correspond to picture element position data stored in the memory and which were output after the lens was interchanged, based on image sensor data corresponding to picture element position adjacent to the picture element position data.
(g) The digital camera further comprises a second memory for storing a picture element defect owned by the image sensor device itself, wherein the correcting section corrects an image failure caused by dirt when there is no defect picture element owned by the image sensor device itself.
(h) The correcting section corrects the image sensor data which correspond to picture element position data stored in the memory and which were output after the lens was interchanged, based on image sensor data corresponding to picture element position which is adjacent to a picture element position stored in the memory.
A digital camera of the present invention whose lens is detachable, comprises: a judging section for judging whether an image failure is caused due to dirt adhering on an image sensor device unit; an illuminating member which is disposed in the vicinity of the image sensor device unit such that irradiation light can enter the image sensor device and which is driven when at least the judgment is made; a dirt position detecting section for storing a position of a picture element of the image sensor device causing image failure when the judging section judged that image failure has been caused; a memory for storing a position of a picture element of the image sensor device corresponding to a dirt position detected by the dirt position detecting section; and a correcting section for correcting the image sensor data output from the image sensor device unit based on picture element position data stored in the memory when a picture is photographed after the lens is interchanged.
A dirt position detecting method of the present invention for a digital camera for judging whether dirt is adhering on an image sensor device unit including an image sensor element provided in a case of the digital camera whose lens is interchangeable, comprises the steps of: shielding light entering the case; irradiating light into the image sensor device disposed in the case; judging whether image failure is caused because dirt adheres by the irradiated light; and storing a position of a picture element causing image failure when it is judged that the image failure is caused.
A preferred mode of the digital camera is as follows.
In the step for irradiating light to the image sensor element, a backlight which irradiates illumination light, from a back side, to a liquid crystal display which displays image data output from the image sensor device, is driven, and the image sensor device is allowed to irradiate light.
With the above configuration, the present invention has operations and effects described below.
By irradiating LCD backlight to the CCD, by detecting picture element of the CCD corresponding to image data causing image failure due to dirt, and by removing picture element defect previously owned by the CCD stored in the camera from the detected picture element, it is possible to detect a position of the picture element having the image failure. If the data corresponding to the picture element position causing the image failure in a new image photographed after the lens is interchanged are corrected from surrounding image data in the picture element position, it is possible to suppress the deterioration of image quality.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.